The present invention relates to improvements made to domestic or professional gas cooking appliances, comprising at least one gas burner equipped with a gas injector which is screwed onto a gas supply tube, the said injector and/or the said tube being engaged through an aperture in a top plate to which the said injector is fixed; the injector and the tube are situated essentially one on each side of the support plate.
Traditionally, these appliances are arranged in such a way that each burner body is supplied with gas via a tube coming from an adjusting tap; the burner body is itself arranged with a pot-shaped part able to receive the removable injector.
To manufacture it, such an arrangement entails at least one operation of connecting the tube to the burner body and one operation of mounting the injector on the burner body. Each of these operations is followed by a leak test operation.
The search for a lower cost of manufacture of gas cooking appliances has led to the aforementioned traditional mounting process being reconsidered and a search for a simpler, swifter and therefore less expensive process.
The essential object of the invention is to propose an improved structure which makes it possible to simplify the methods of assembly, to speed up the assembly time and finally to reduce the cost of manufacture.
To these ends, a gas cooking appliance such as mentioned in the preamble is characterized, while being arranged in accordance with the invention, in that a radially extending annular flange is provided on the supply tube, which flange is situated under the support plate, and clamped in a sealed fashion against the peripheral edge of the aperture and/or bearing surface of the injector so that when the injector and the supply tube are being assembled, one on each side of the support plate, a seal is produced between the tube and the injector, on the one hand, and between the top and the underside of the support plate around the edge of the aperture, on the other hand, and at the same time to mechanically hold the injector secured to the supply tube in a centered position in the aperture with the outlet orifice of the injector situated in a predetermined axial position above the support plate. In a preferred embodiment, the injector and the end or the region near the end of the supply tube are threaded and are secured by being screwed together.
Thanks to the arrangements of the invention, there then remains only the single operation of directly assembling the injector with the supply tube, by screwing, the structures being such that this simple assembly brings collaborating surfaces together to correctly (axially and radially) position the injector with respect to the support plate and seals as required. What is more, the special structures employed for this, and a number of embodiments of which are indicated hereinafter, are obtained by simple machining operations, particularly forming or pressing, bending, etc, which are inexpensive and merely require equipment which is none too complex.
Such an arrangement may lead to various embodiments:
in one embodiment, the annular flange is situated beneath that end of the tube which is secured to the injector and the peripheral edge of the aperture is clamped in a sealed way between the said annular flange of the tube and a bearing surface of the injector, which surface is formed by the lower end of the injector or an annular shoulder surrounding the injector;
in another embodiment, the annular flange is situated beneath that end of the tube which is secured to the injector and the peripheral edge of the aperture is folded over and clamped in a sealed way between the said annular flange of the tube and a conical bearing surface provided around the injector;
in yet another embodiment, the annular flange is situated in close proximity to the end of the tube and above that part of the tube which is secured to the injector, and the end of the tube surmounting the annular flange is folded over to trap the peripheral edge of the aperture into contact with a conical bearing surface of the injector; in an alternative form of embodiment it is possible to envisage an elastic clip being inserted between the folded-over end of the tube and the support plate.
In a simple way, the flange may consist of a radially protruding annular fold of the wall of the tube.
The arrangements according to the invention seem to find a particularly advantageous, although not exclusive, application in the case where the support plate is none other than the top plate of the cooking appliance, in other words when the injector is secured directly to the top plate, which arrangement leads to the omission of the burner pot and any members there might be for mounting the injector in this pot. In such a field of application of the arrangements of the invention, this culminates in an overall structure which combines substantial structural and assembly simplifications and is therefore appreciably more economical than the structures of the prior art.